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Smardt/Killtech

I am having a problem with the bozer gen3 killtech communicating with my compressors. Periodically they will drop off line like they are not communicating through the modbus. Sometimes the chiller will stop and go into alarm due to lost comm, sometimes just shut down and reset itself. When I find it not communicating I sometimes can simply chqanged screens an get comm back. All connections seem to be ok thinking there may be a curupt file in the killtech. Anybody seen this?
P.S. I have this occuring on two chillers at two different sites.

Modbus/485 have been checked, One of the chillers is about 1.5 year old. The other was one of the original versions of killtech panels installed 4 years on a retrofit project for a Carrier 23XL that was working perfect, never had a problem until another contractor told them they should update it with the latest and greatest (killtech upgrade). Thinking I just need to wipe out all existing files and replace with new unless some one can shed some light. Custmer just wants it to work at this point. Love the product but trying to wipe the mud clean to get the customer to think so is becoming difficult.

first off make sure all the stop bits on the compressors and the controller are set to 1...

the gen 3 came out before the a program had been fully developed to run on controllers hard drive...

if you had an early shipment you will be running off a usb flash drive... the controller will run perfectly fine on the flash drive...

with the flash drive you will use one controller comm port for the compressors and one comm port for the kiltech i/o.

there is a retrofit available to install a new program... (wiring changes needed)

The new program has faster alarm logic as well as some other features mainly developed for process loads... the most visible change is the HOA switch that is on the upper right on the main screen...

I am not sure i like it but at least the customer can cycle the machine without going into the hidden menu...

be aware that when the panel goes to sleep, and you touch the screen to wake up it would be very easy to cycle the remote call... i am placing labels on the panel so the customers know where to touch the screen to wake it up...

with the new program there is only one communication port that is used... the other port is reserved for the ems interface module...

the communication will come from the controller and go thru the signal converter... there are two types...

optically isolated (4 pin terminal) and the non optically isolated (3 pin terminal) the shielding termination on the comm line is very specific to what type of signal converter you have...

after converting from RS232 to RS485 the comms go to and thru the compressor i/o's and finally land on the kiltech i/o...

what we were experiencing was loss of comms on a compressor when the compressor/ machine demand was near full load... (high noise)

1. go thru the 480 volt grounds... start from the compressors move thru the power panels and make sure you have good tight connections all the way back to the mcc...

2. make sure that the grounding screw on the compressor back plane board behind the pwm module on the bottom right is tight... this is a serious grounding path for the electronics...

3. if you still have some irregularities try switching your bmcc modules from one compessor to the next... keep in mind that the slave adress will stay with the bmcc.

if the comm problem stays with the bmcc you have a "leaking" RS485 driver in the bmcc...

in our situatioin we had a spare bmcc that we installed in the problem compressor and we have had no trips since... comms steady at 98 - 100%

this was very difficult to find and i hope this will be of some help to you...

these machines are high speed vfds... you have to have good grounds!

on the comm cable Smardt has spec'd some Beldon 3108a cable (90% tinned) that is 1.80/ft. I found and installed it but i think it is overkill...

Note:

in hindsight i dont feel like the program upgrade was a mandatory step for the resolution of this problem...